This invention relates generally to highway, street, and related signs, particularly those that are designed to break or shear off at a specific location on the signpost when struck by a forceful blow such as by an automobile.
Highway and street signs and their signposts are commonly placed on sidewalks and shoulders of roadways, where they are exposed to a substantial risk of damage from errant automobiles, snowploughs, oversized vehicles, etc. Signposts are generally embedded into dirt or cement to hold them secure from such forces as wind pressure on the face of the sign and human vandals, yet it is often desirable from a safety standpoint to have them break off in a particular location upon a high-force impact such as by an automobile. For example, it is preferable to have the sign shear off and fall away from the direction of impact so that the sign does not fly through the windshield of the car that hit it and thereby injure its occupants, or to have it break off rather than bend and produce a navigational hazard for pedestrians and/or traffic.
Additionally, it is desirable to be able to repair the signpost, rather than to replace it by removing it completely from the dirt, cement, or other substrate in which it is embedded. It may be less expensive and easier to effect a repair if the signpost has been broken in a predetermined area rather than bent by the force of the impact. Toward this end, several means exist to fasten signposts to anchoring devices embedded into the substrate which will break away upon impact and have some means of replacing broken or bent signposts.
One type of breakaway signpost, set forth in U.S. Pat. Nos. 5,957,425, 5,887,842, and 5,794,910, for example, employs an anchor embedded in a substrate and a signpost attached to the anchor and extending above the ground. The anchor is generally a length of metal (tube or formed strip) of the same type and configuration as the signpost. A stress transfer strip or block of metal is inserted between overlapping segments of the anchoring piece and the signpost. The three piecesxe2x80x94the anchor, the stress transfer strip, and the signpostxe2x80x94are generally bolted together in two or more places through aligned holes in the pieces and held securely by tightening the bolts. This splice arrangement is designed as a stress transfer mechanism, whereby the bar stiffens the signpost against the wind and serves to reduce momentary (e.g., wind-derived) stresses on the individual bolts of the assembly, but at the same time provides a predictable breakaway joint upon impact.
A disadvantage of this type of breakaway signpost is that the mechanisms may work better when the sign is struck from a frontal direction compared to other directions, because the bolts are designed to shear upon impact, and a frontal blow will put stress on the top bolt first and then the second, allowing them to break sequentially. A side blow may distribute the stress on the bolts more evenly, allowing them to hold and the signpost to bend rather than break away. Another disadvantage is that once the signpost has broken off, the anchor post is left sticking up above the substrate. This latter disadvantage may pose a risk of damaging the undercarriage of the vehicle which struck the sign. Even a small length of anchor post above the substrate is problematic when the sign is located on a sidewalk or heavily traveled pedestrian route, since the anchor post may not be seen by a pedestrian, who could suffer an injury because of it.
Other breakaway signpost designs have addressed one or both of these problems to at least some extent. One design uses a connector which attaches to each end of a sign post and a ground anchor post, and separates the ends by a weakened region designed to shear off upon impact. Examples of such connectors can be seen in U.S. Pat. Nos. 5,480,121 and 5,782,040. These designs will shear equally well in response to an impact from any direction, but can still leave a portion of the post sticking up above the ground.
U.S. Pat. No. 4,553,358 discloses a specially shaped angle iron anchor socket, designed to accommodate a conventional hat section channel signpost, which is driven into the ground. When the signpost is put into this socket and a compression leg is installed to force the post against the angle iron of the socket, the tension on the signpost below the ground creates a zone which is designed to shear when the signpost is struck by a vehicle.
While the device disclosed in this patent addresses the problem of ground-level shearing, it can only be used with a single type of signpost, the hat section channel signpost, and is not adaptable to a tubular signpost, for example.
All of the above designs, while addressing various problems, still do not solve certain problems. Most of the designs have the problem that they are cumbersome and time-consuming to install, move, and repair, particularly by one person, because they require welding of the component parts, or screwing and unscrewing of nuts and bolts.
It should be appreciated, therefore, that there is still a need for a signpost assembly mechanism that is quick and easy to install, remove, and replace if damaged, and which further is able to provide reliable ground-level shearing upon impact from any direction.
The present invention is embodied in a signpost assembly having a spring-loaded connector which is fast and easy to install, to remove while the signpost is intact, and to replace when the signpost is damaged. Upon a forceful impact from any direction, a signpost and anchor secured by the spring-loaded connector of the invention will shear at any pre-set level including at ground level as is generally preferable.
The signpost assembly of the present invention is designed for connecting a signpost to an anchor member. It includes a signpost having a pair of openings, a connector having a bracket with at least a first support side and a second support side, and a base connecting the support sides. Each support side has an opening. The assembly also has a first pin and a second pin, each having an alignment knob, and a spring biasing the first pin and the second pin from a first position where the alignment knobs are close together to a second position where the alignment knobs are spaced further apart than in the first position. The openings of the first and second support sides are adapted to receive a respective alignment knob, so that when the pins are placed between the first and second support sides, the alignment knobs protrude through the openings in the support sides of the bracket. The bracket is adapted to fit between the pair of openings of the signpost such that the openings of the first and second support sides are aligned with the pair of openings, and the alignment knobs protrude through the aligned openings to secure the bracket to the signpost.
A feature of the invention is the spring biased pin/connector assembly. The advantage of this assembly is that no bolts are required to secure the signpost to an anchor member in the ground. This makes installation of the sign fast and easy.
Another feature of the invention is a hinge associated with the support sides of the bracket. This feature facilitates easy removal of the signpost from the anchor member or the connector from the signpost by allowing the support sides to be squeezed together around the hinge from an expanded position to a position where the spring is compressed and the alignment knobs are pulled from the openings in which they rest. As with the installation, no screwing or unscrewing of bolts is needed and the procedure is quick and easy.
The invention also features an anchor member which has at least one pair of openings opposite each other and whose cross sectional area is sufficiently large to fit the cross sectional area of the signpost within it. The anchor openings are large enough for the alignment knobs to fit within them. When the signpost is slid into the anchor member, each opening of the signpost is aligned with the openings of the anchor member, and the alignment knobs of the spring-loaded connector can pop into the openings of the signpost and the anchor. An advantage of this feature is that the signpost can easily be inserted into a pre-installed anchor member.
Another feature of the invention is installation of the anchor member into the ground or a substrate so that no portion of it is above the substrate level. Optionally, the anchor member is reinforced by a strengthening sleeve which has at least one pair of openings opposite each other and whose cross sectional area is sufficient to fit the cross sectional area of the anchor within it. The strengthening sleeve openings are large enough so that the alignment knobs fit within them, and the openings are aligned with the anchor openings. An advantage of these features is that ifthe post is struck forcefully, for example by a vehicle, it will shear off at ground level rather than bend or break at a higher level where it could pose a danger to vehicles or pedestrians.
Another feature of the invention is that the signpost assembly is easily disassembled because the support sides can be moved between a first expanded position and a second compressed position. This movement can be achieved by rotation around a hinge in the base or by bending flexible support sides. An advantage of this is that the sign can be moved if desired, and easily repaired if broken.
Another feature of the invention is a compression flange adjacent to each support side, each compression flange having a wing portion which is parallel to but inset from the support sides, and which can further comprise a hole through which a spring release tool can be threaded and two indentations on the edge of the upper end adapted for grasping by the digits of a hand. The advantage of this feature is that the spring-loaded connector can be easily removed by hand from a broken signpost in the field.
Also provided in the invention is an insert and removal tool having a handle into which is fixed a long blade and a short blade which are formed in a xe2x80x9cVxe2x80x9d shape where they connect to the handle. The blades are parallel to each other at their ends distal to the handle, and are adapted to receive the bracket, spring and first and second pins so that the spring is compressed when the bracket is seated in the insert and removal tool. The advantage of this feature is that the spring35 loaded connector can be easily installed or removed from an intact sign.
The invention also includes a method for installing a signpost into a substrate, the method comprising providing a signpost and an anchor member each having at least one pair of openings opposite each other, the anchor member""s cross sectional area being sufficient to fit the cross sectional area of the signpost within it, a bracket having at least a first support side and a second support side and a base connecting the support sides, each support side having an opening, and a spring biasing apart a first pin and a second pin, each pin having an alignment knob at one end and a stop flange adjacent to the alignment knob. The stop flange has a spring side and a bracket side. The method involves inserting the anchor member into the substrate, placing the spring biased pins inside the bracket, placing the bracket inside the signpost, aligning the openings in the first and second support sides with the openings in the signpost and the openings in the anchor member. The openings in the first and second support sides are adapted to receive a respective alignment knob and are smaller in diameter than the stop flange, and the openings in the signpost and anchor are sized to receive the alignment knob. The pins are positioned so that the alignment knobs protrude through the openings in the signpost and into the openings in the anchor. The bracket side of the stop flange stops the outward travel of the pins, and the pins are held in place by the spring""s tension against the spring side of the stop flanges.
A feature of the invention is that the signpost can be removed from the anchor. The method for removing the signpost involves compressing the spring so that the alignment knobs are drawn within the signpost, and the signpost is withdrawn from the anchor.
Other features and advantages of the present invention will become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.